The Nike Corporation is making a big investment to lift American distance running out of mediocrity. The company, which produces athletic shoes and other sportswear, has immersed six elite runners in an unconventional conditioning program that artificially simulates the effects of high altitude on the body. So far, the effort, code-named the "Oregon Project" has yielded a double Olympic qualifier and one alternate for the Athens Games.

Runner Dan Browne surges on the final lap of an Olympic trials tune-up race in Eugene, Oregon. Crossing the finish line he shows pleasure with his 5000-meter time by tossing his designer sunglasses into the crowd.

Yet the Oregon native has finished in fourth place behind three runners from Kenya. That's typical for American distance runners. The last American man to win an Olympic medal in a distance event was Frank Shorter in Montreal, back in 1976. Dan Browne has qualifed for the Olympic marathon and 10K in Athens, and says he doesn't intend to nip at the Africans' heels forever. "Ultimately what we're trying to do is reestablish American distance running as something other than just a sideshow," he said. "You know, I'd like to get to the point where we can compete and beat some of the Africans on a more regular basis."

Browne is one of the original members of Nike's Oregon Project. In early 2002, he and five other promising runners signed on to an experiment to see if the best technology and coaching that Nike's money could buy could mold a new generation of champions.

The hermetically sealed altitude room is a key part of the regimen, called "Live High-Train Low." It's where Browne sleeps most nights that he's home.

The lean 29-year-old switches on a machine in the closet. It runs all night filtering out oxygen to simulate the rarified air of a high altitude.

"I monitor this daily just to make sure that I'm not sleeping up on Mt. Everest," he said. "I definitely don't want to go above like 16,000 or 17,000 feet."

Browne spends about nine hours a day in the oxygen-deprived bedroom. His teammates sleep and relax in another house Nike remodeled. The living areas there, as well as the bedrooms, also have altitude controls.

"You would definitely notice it within about 10 minutes," said Browne. "You would notice you are becoming out of breath and you're breathing deep and something doesn't quite feel right. But I have gotten to the point where I adjust pretty quickly and I know the feeling."

Technology suspends Browne and the other Oregon Project runners somewhere in the high Rocky Mountains by night. By day, they just walk out the front door and they're in Portland, practically at sea level.

According to Scott Trappe, Director of Ball State University's Human Performance Lab, altitude training is popular because it naturally stimulates the body's production of red blood cells. The more red blood cells you have, the more oxygen gets to your muscles, and the more endurance you have. The drawback is that you can't work out at maximum intensity in such thin air. Mr. Trappe says the "Live High-Train Low" machinery lets runners have the best of both worlds.

"I think there's enough science behind it to suggest that it is certainly worth doing," he said. "If the costs were less I think we'd probably see more athletes doing that." Corporate spokespeople at Nike headquarters in Beaverton declined to discuss the subject. They won't say how much money the company has spent on Oregon Project gizmos and athlete contracts or how long they'll stick with it. Tom Jordan, who organizes elite track meets, applauds Nike's effort, but says the team members have a long way to go to catch up with Africa's best runners.

"I've always said what we should do is simply make them American citizens. But that's the easy way," said Mr. Jordan. "The difficult way is to take the talent we have and develop it."

The International Olympic Committee and the U.S. Anti-Doping Agency have looked into artificial altitude training and raised no objections, other than to say portable altitude tents will not be allowed in the Athletes Village at the Athens games next month.